This invention pertains to a packaging system, and more particularly to a system for enclosing a compressible stack of articles within a sleeve.
Various mechanisms are known for packaging a compressible stack of articles, such as a stack of paper towels or the like. One such device is enclosed in Lucas et al U.S. Pat. No. 3,729,886 issued May 1, 1973, and entitled Method and Apparatus For Banding Articles. This patent discloses advancing the stack of articles by means of a pair of conveyors defining facing upper and lower runs. The conveyor runs converge toward each other, so that the stack is compressed as it is being advanced by the conveyors. A sheet of material is applied to the top of the compressed stack, and is folded down along the sides of the stack and under the bottom of the stack, all while the stack remains under compression. An adhesive is applied between areas of the sheet which are folded onto each other, to form the sheet into a band which encircles the stack of articles. The stack is advanced while remaining under compression, allowing the adhesive to set, after which the banded stack is discharged from between the conveyor runs. The stack undergoes decompression, and is retained within the band by friction between the stack and the band.
An improved version of the above-summarized machine involves supplying upper and lower webs of material to the top and bottom, respectively, of the compressed stack. The top web is folded down to partially cover the sides of the stack, and the bottom web is folded up to partially overlap the edges of the top web. Adhesive is applied between the overlapping portions of the top and bottom webs, and rollers apply pressure thereto. The stack remains under compression until the adhesive sets, after which it is discharged from between the upper and lower conveyor runs.
It is an object of the present invention to provide an improved mechanism for packaging a compressible stack of articles, such as paper towels or the like. It is a further object of the invention to provide an article packaging system which results in production of a clean and neat package for the stack. Yet another object of the invention is to provide a compact and efficient packaging system for producing a packaged stack of articles.
In accordance with one aspect of the invention, a system for packaging a compressible stack of articles includes an article feeding mechanism for supplying the stack of articles in a compressed state, and a sleeve feeding mechanism for supplying a collapsible tubular sleeve in a collapsed condition, with the sleeve defining at least one open end. The invention further includes a sleeve opening mechanism for moving the sleeve from its collapsed condition to an open condition, and an inserting mechanism for inserting the compressed stack of articles into the open end of the sleeve when the sleeve is moved to its open condition by the sleeve opening mechanism. The invention further includes a removing mechanism for removing the sleeve and the stack of articles from the sleeve opening mechanism, which results in decompression of the stack and engagement of the stack with the sleeve, to retain the stack of articles within the sleeve by friction.
The sleeve opening mechanism consists of a pair of prongs, movable between a first collapsed position in which the prongs are close together, and a second opened position in which the prongs are moved apart. The sleeve feeding mechanism functions to place the sleeve onto the prongs when the prongs are in their first collapsed position. Movement of the prongs to their second opened position functions to open the sleeve, and the inserting mechanism is operable to insert the stack of articles into the open end of the sleeve between the prongs. The prongs are mounted to a pivoting turret mechanism which functions to move the prongs between a sleeving station, an inserting station, and a removal station. At the sleeving station, the prongs are in their first collapsed position and the sleeve feeding mechanism functions to place the sleeve onto the prongs. The sleeve opening mechanism functions to move the prongs from their first collapsed position to their second opened position during movement of the prongs between the sleeving station and the inserting station. At the inserting station, the stack of articles is inserted into the sleeve between the prongs. At the removal station, the removing mechanism functions to remove the sleeve and the stack of articles from the prongs.
The sleeve opening mechanism includes a guide track with which at least one of the prongs is interconnected. The guide track is arranged to provide movement of the prongs between their open and closed positions as the prongs are moved by pivoting movement of the turret mechanism.
The sleeve feeding mechanism functions to construct a sleeve from a parent roll of web material, by unwinding the web material from the parent roll, and folding and gluing the web material into a collapsed, folded tube. A cutting mechanism functions to cut the collapsed, folded tube into collapsed sleeves of predetermined length. The feeding mechanism includes a pair of rollers defining a nip for receiving the collapsed sleeve therebetween. Each roller includes one or more suction ports to which suction is applied. The suction ports function to draw the walls of the collapsed sleeve apart, to partially open the sleeve as the sleeve is propelled by the rollers toward and onto the sleeve opening mechanism.
The invention also contemplates a method of packaging a compressible stack of articles. The method involves the steps of providing a sleeve in a collapsed condition, with the sleeve defining at least one open end, and moving the sleeve to an open position for opening its open end. The method further includes compressing the stack of articles, inserting the compressed stack of articles into the open end of the sleeve, and decompressing the stack of articles, so that the articles engage the sleeve and are retained within the sleeve by friction. The details of the method are substantially in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.